Cisco Systems OL-5490-01 Manuale Utente

The VPN Client works with a Cisco VPN device to create a secure connection, called a tunnel, between 
your computer and a private network. It uses Internet Key Exchange (IKE) and Internet Protocol Security 
(IPSec) tunneling protocols to establish and manage the secure connection. 

The steps used to establish a VPN connection can include:

Negotiating tunnel parameters (addresses, algorithms, lifetime)

Establishing VPN tunnels according to the parameters

Authenticating users (from usernames, group names and passwords, and X.509 digital certificates.)

Establishing user access rights (hours of access, connection time, allowed destinations, allowed 
protocols)

Managing security keys for encryption and decryption

Authenticating, encrypting, and decrypting data through the tunnel

For example, to use a remote PC to read e-mail at your organization, the connection process might be 
similar to the following:

Connect to the Internet.

Start the VPN Client.

Establish a secure connection through the Internet to your organization’s private network.

When you open your e-mail

The Cisco VPN device

Uses IPSec to encrypt the e-mail message

Transmits the message through the tunnel to your VPN Client

The VPN Client

Decrypts the message so you can read it on your remote PC

Uses IPSec to process and return the message to the private network through the Cisco VPN 
device.